The effects of re-irradiation on the chemical and morphological properties of permanent teeth

• Published in: Radiation and environmental biophysics 2024-05, Vol.63 (2), p.283-295
• Main Authors: dos Santos, Thais Tedeschi, Mattos, Vicente Silva, Molena, Kelly Fernanda, de Paula-Silva, Francisco Wanderley Garcia, de Oliveira, Harley Francisco, Faraoni, Juliana Jendiroba, Nelson-Filho, Paulo, de Castro Neto, Jarbas Caiado, Palma-Dibb, Regina Guenka, de Queiroz, Alexandra Mussolino
• Format: Article
• Language: English
• Subjects: Biological and Medical Physics; Biophysics; Dental enamel; Dental Enamel - chemistry; Dental Enamel - radiation effects; Dentin; Dentin - chemistry; Dentin - radiation effects; Ecosystems; Effects of Radiation/Radiation Protection; Environmental Physics; Head & neck cancer; Humans; Hydroxyapatite; Irradiation; Molar - radiation effects; Molars; Monitoring/Environmental Analysis; Morphology; Physics; Physics and Astronomy; Radiation damage; Radiation therapy; Raman spectroscopy; Scanning electron microscopy; Spectrum analysis; Spectrum Analysis, Raman; Statistical analysis; Teeth; Tooth - radiation effects; Variance analysis; X-ray spectroscopy
• ISSN: 0301-634X; 1432-2099; 1432-2099
• DOI: 10.1007/s00411-024-01068-1

This study aimed to assess the in vitro effects of re-irradiation on enamel and dentin properties, simulating head and neck cancer radiotherapy retreatment. Forty-five human permanent molars were classified into five groups: non-irradiated; irradiated 60 Gy, and re-irradiated with doses of 30, 40, and 50 Gy. Raman spectroscopy, scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDS) were employed for analysis. Raman spectroscopy assessed intensity, spectral area, and specific peaks comparatively. Statistical analysis involved Kolmogorov–Smirnov and One-Way ANOVA tests, with Tukey’s post-test (significance level set at 5%). Significant changes in irradiated, non-irradiated, and re-irradiated enamel peaks were observed, including phosphate (438 nm), hydroxyapatite (582 nm), phosphate (960 nm), and carbonate (1070 nm) ( p   0.05), leading to interprismatic region degradation, enamel prism destruction, and hydroxyapatite crystal damage. Dentin exhibited tubule obliteration, crack formation, and progressive collagen fiber fragmentation. EDX revealed increased oxygen percentage and decreased phosphorus and calcium post-reirradiation. It is concluded that chemical and morphological changes in irradiated permanent teeth were dose-dependent, exacerbated by re-irradiation, causing substantial damage in enamel and dentin.